The invention relates to an entry and security system installed on a vehicle, and particularly, to a combination passive security and remote entry security system capable of changing the state of a latch mechanism mounted on a vehicle from a secured state to an unsecured state.
Various systems and methods for providing a signal to unlock a vehicle door have been presented in the prior art. One such system is a Remote Keyless Entry (RKE) system. The RKE system of the prior art includes a portable transmitter, or fob, that transmits a signal to an antenna mounted on a vehicle in response to a user request. The signal causes a vehicle controller to move a lock mechanism mounted on the vehicle frame from a secured (or locked) state to an unsecured (or unlocked) state or vice versa. The fob of the RKE system typically includes one or more buttons for initiating various actions (e.g., locking or unlocking doors to the vehicle or to the trunk of the vehicle or initiating a xe2x80x9cpanicxe2x80x9d alarm) when a user depresses one of the buttons.
Another prior system for providing a signal for unlocking a vehicle door is a Passive Security (PS) system. The PS system of the prior art includes a fob that transmits a signal requesting a vehicle controller to change the state of the latch mechanism mounted on the vehicle frame from a secured state to an unsecured state. The initiation of the signal occurs when the fob is adjacent to the vehicle.
Yet another prior system for providing a signal for unlocking a vehicle door is a Modified Passive Security (MPS) system. The MPS System of the prior art is similar to the PS system except that the initiation of the signal requesting the lock mechanism to move from an unsecured state to a secured state occurs when a user actuates a door handle on the vehicle frame.
Accordingly, the invention provides a Vehicle Security (VS) System having generally at least one antenna, a controller and at least one fob. The VS system is adapted to be mounted on a vehicle having a frame. The frame has at least one enclosure (i.e., door) movable between open and closed positions. Each enclosure has a latch mechanism for securing the door in the closed position. The securing of the door prevents unauthorized or inadvertent movement of the door to the open position.
Each antenna of the VS system is mounted on the vehicle frame, and transmits and receives communication signals with the fobs. The controller is mounted on the frame and is electrically connected to each of the antennas and each of the latch mechanisms. The controller provides a signal to the latch mechanisms capable of moving the latch mechanism from the secured state to the unsecured state or vice-versa.
In one embodiment of the invention, each of the fobs transmit either an RKE signal or a PS signal to the controller through the vehicle antennas. The RKE signal is transmitted when the user depresses a button on one of the fobs requesting the latch mechanisms to be in the secured or unsecured state. The PS signal is transmitted when one of the fobs is within a radiation pattern emitted by one of the antennas. The radiation pattern can be continuously radiated by the antenna or be initiated when a user attempts entry to the vehicle. Thus, the VS system allows for the benefits of both RKE systems and PS systems.
In another embodiment of the invention, more than one antenna may be mounted on the vehicle allowing a user to unlock only a specific door while attempting to enter the vehicle. For example, if the vehicle has two doors, the driver side door could xe2x80x9cunlockxe2x80x9d while the user approaches or attempts to enter that door while carrying a fob. Similarly, the passenger side door could xe2x80x9cunlockxe2x80x9d while the user approaches or attempts to enter that door while carrying a fob. In the alternative, the VS system allows the user the flexibility of xe2x80x9cunlockingxe2x80x9d of all of the doors if the user approaches or attempts to enter any of the vehicle doors while carrying a fob.
In yet another embodiment of the invention, the PS signal allowing communication between the vehicle and the fobs is generated only when one of the fobs is within the vicinity of one of the vehicle doors. That is, each of the radiation patterns emitted by the antennas is a unidirectional radiation pattern, and the fobs will provide PS signals for unlocking the vehicle door only if they are within one of the unidirectional radiation patterns. Preferably, the unidirectional radiation patterns are transmitted such that they are directly adjacent to the vehicle""s enclosures.
Additionally, the VS system includes an improved encryption method for establishing secured communications between the antennas and the fobs. Specifically, the vehicle controller has a key or key code (which is stored in both the fob and the vehicle controller). The vehicle controller uses the key to form a challenge signal by xe2x80x9ccombiningxe2x80x9d a random number with a challenge data packet that includes challenge data. The vehicle controller then transmits the challenge signal. The vehicle controller generates an expected number from the random number. At about the same time, the fob receives the challenge signal from the vehicle antenna and xe2x80x9cseparatesxe2x80x9d the random number from the challenge data packet. The fob generates an answer using the key and the random number, and then the fob generates a response signal by using the key to xe2x80x9ccombinexe2x80x9d the answer with a response data packet including response data. The fob then transmits the response signal to the vehicle.
The vehicle controller receives the response signal from the fob and xe2x80x9cseparatesxe2x80x9d the answer from the response data packet. If the two numbers (i.e., the answer and the stored or xe2x80x9cexpectedxe2x80x9d number) are the same, the vehicle controller provides a signal changing the state of the vehicle to an xe2x80x9cunlockedxe2x80x9d state. If more than one user with a fob is attempting to enter the vehicle at the same time, the vehicle entry system will give priority to one fob over another fob to prevent conflicting actions from being initiated by different fobs.
Furthermore, the invention provides a VS system that initiates three steps of validation when a fob is attempting to passively unlock a vehicle door. First, the fob verifies that a received challenge signal has the proper signal strength in order to ensure that the signal detected by the fob is not simply noise and that the fob is within the radiation pattern of the antenna. In other words, if the fob is not within a predetermined distance of the antenna, the strength of the signal radiating from the antenna will be too weak for the fob to continue. Throughout this period, the microprocessor in the fob is in a xe2x80x9csleep mode.xe2x80x9d Next, the fob provides bit-check verification of the challenge signal to make sure that the signal received from the antenna is proper for the VS system incorporating the invention. That is, the fob calculates the time between segments of challenge data to determine if the timing is proper for the VS system. The fob will not transmit a response signal unless the interrupt time is correct. Lastly, the vehicle entry system proceeds through data packet validation. Data packet validation is the process whereby the system determines if the fob has the same vehicle code as the stored vehicle code. By going through a three-step process, the fob consumes less power since it does not attempt to signal a vehicle door based on a false input signal.
The invention also provides for a distributive VS system to be mounted in a vehicle having a frame. The system includes at least two antennas each having a respective radiation pattern. The first antenna is adapted to be mounted on the frame in a first position and the second antenna is adapted to be mounted on the frame in a second position spaced from the first position so as to prevent the first and second radiation patterns from interfering with one another. The radiation patterns can be unidirectional radiation patterns, and the system includes at least one fob configured to remotely communicate with each of the antennas. The first fob communicates with the first antenna when it is within the first radiation pattern and communicates with the second antenna when it is within the second radiation pattern.
The frame includes at least one enclosure (e.g., vehicle door) mounted on the frame with each enclosure having a latch mechanism. Each vehicle door includes an actuating device (e.g., door handle). The latch mechanism can be switched between a secured and an unsecured state. In the secured state, the latch mechanism prevents unauthorized or inadvertent operation of the actuating device to open the enclosure. The first latch mechanism is associated with the first antenna such that the latch mechanism moves between the secured and unsecured state when the fob is within the first radiation pattern. The second latch mechanism is associated with the second antenna such that the latch mechanism moves between the secured and unsecured state when the fob is within the second radiation pattern. In one embodiment of the invention, the fob initiates communication with one of the vehicle antennas only after being challenged by the vehicle when a user actuates the actuating device on the vehicle. In a second embodiment, the fob initiates communication with one of the vehicle antennas when a user, holding a fob, enters the radiation pattern of the vehicle antenna.
The fob of the VS system also includes a remote keyless entry (RKE) control for generating a first RKE signal between the fob and at least one of the vehicle""s antennas to move the latch mechanisms from the secured state to the unsecured state. Additionally, the RKE control generates a second RKE signal from the fob to at least one of the antennas to move the latch mechanisms from the unsecured state to the secured state.
The invention also provides a VS system in which the fob communicates with one of the vehicle antennas to move the latch mechanism from a locked state to an unlocked state in a three-step process. First, the fob verifies that a received signal has the proper amplitude and frequency to be a challenge signal from the vehicle antenna. Second, the fob verifies that the challenge signal has a proper timing to be a challenge signal from the vehicle antenna. If the challenge signal has the proper amplitude and timing or time frame, the VS system proceeds through data packet validation.
The data validation process includes transmitting a challenge signal including a challenge data packet from the vehicle antenna to a first fob antenna. In response to receiving the challenge data packet, the fob authenticates the challenge data packet. If the authentication of the challenge data packet has been met, the fob generates a response signal including a response data packet. The response signal is transmitted from the first fob antenna to the vehicle antenna. In response to receiving the challenge data packet, the vehicle controller authenticates the response data packet. The latch mechanism changes from the secured state to the unsecured state if the response data packet has been authenticated. The two authentication acts will only be met if the vehicle electronic key code and the fob electronic key code are the same.
The invention also provides a VS system wherein, if there is more than one fob within the radiation patterns, a first fob will take priority over the remaining fobs. That is, the first fob will proceed in attempting to change the state of the latch mechanism from the secured state to the unsecured state by using the three step process above, and a second fob will also attempt to unlock the vehicle door by also following the three-step process above. However, the second fob will not transmit the response signal until a time period has elapsed which is sufficient to allow the first fob to respond. In other words, only one fob at a time will respond. This ensures that the transmitted signal will not be either distorted or incorrect due to more than one fob engaging in communication within the radiation patterns of the antennas at the same time.
It is an advantage of the invention to combine a PS system with a RKE system. The combination PS system and RKE system allows for the benefits of each system. More specifically, the invention can remotely secure or unsecure a vehicle and passively unsecure a vehicle with the same fob.
It is another advantage of the invention to provide more than one antenna in the VS system. Providing more than one antenna reduces power consumption within the fob and the vehicle, reduces unexpected vehicle unlocking, and allows for the fob to initiate a PS signal to any specific vehicle enclosure upon approaching or attempting to enter that enclosure.
It is another advantage of the invention to have a VS system with an antenna providing unidirectional PS radiation patterns. This allows the VS system to unlock an enclosure when the fob is within a certain area in relation to the vehicle. For example, as the user with a valid fob is nearby the driver side door, the driver side door will unlock. However, continuing the example, the door will not unlock when the user is near the front of the car.
It is another advantage of the invention to allow more than one fob to be used with the VS system without having the fobs conflict.
It is another advantage of the invention to use a three-step process to validate data received by the fob. This will prevent the fob from consuming power while trying to unlock a vehicle based on false signals.